U.S. Pat. No. 5,889,401 and U.S. Pat. No. 6,541,964 describe methods and apparatuses for eddy current measurements on components, for example fuel rods, in nuclear power reactors. As is mentioned in these documents, it can be important to be able to carry out measurements of for example the thickness of layers that may exist on such components. The layer can for example be an oxide layer. Fuel rods for nuclear reactors can also have a layer of another kind, for example a so-called crud layer. The crud layer is usually located outside of the oxide layer. The crud layer can be magnetic, which makes the measurement of the thickness of the oxide layer more difficult. It is, however, possible to measure the thickness of the oxide layer and/or the thickness of the crud layer, even if the crud layer is magnetic, with a suitable calculation model, for example of the kind that is described in the above cited documents. The measurement can also be carried out concerning other properties than layer thickness, for example concerning the content of hydrides in the component. The measurement is carried out with a measurement probe which is arranged in the immediate vicinity of the measurement object. The measurement probe is connected with a measurement equipment via at least one cable. The properties of the cable can influence the measurement result, since the cable has a certain transfer function. In connection with measurements, a calibration therefore needs to be carried out, inter alia concerning the influence of the cable on the measurement result, in order to obtain a correct measurement result.